GPUImmediate: Add system wide workaround for wide line

This makes wide line supported on MacOS and other implementation that
does not support wide line by default.

This workaround works for all Line types but only if using one of the 5
default shaders.

The workaround is completely isolated and invisible to the outside. It has
no side effect.

Note: This does not affect the GPUBatch drawing.

1 files changed, 9 insertions, 0 deletions

diff --git a/source/blender/gpu/intern/gpu_immediate_private.hh b/source/blender/gpu/intern/gpu_immediate_private.hh
index 38db8131942..b867a85bb8b 100644
--- a/source/blender/gpu/intern/gpu_immediate_private.hh
+++ b/source/blender/gpu/intern/gpu_immediate_private.hh
@@ -55,6 +55,15 @@ class Immediate {
   /** Batch in construction when using immBeginBatch. */
   GPUBatch *batch = NULL;
 
+  /** Wide Line workaround. */
+
+  /** Previously bound shader to restore after drawing. */
+  GPUShader *prev_shader = NULL;
+  /** Builtin shader index. Used to test if the workaround can be done. */
+  eGPUBuiltinShader builtin_shader_bound = GPU_SHADER_TEXT;
+  /** Uniform color: Kept here to update the wideline shader just before immBegin. */
+  float uniform_color[4];
+
  public:
   Immediate(){};
   virtual ~Immediate(){};